Spring - Spring配置文件-Spring配置数据源详解

一般方式配置数据源

数据源（连接池）的作用

• 数据源(连接池)是提高程序性能如出现的

• 事先实例化数据源，初始化部分连接资源

• 使用连接资源时从数据源中获取

• 使用完毕后将连接资源归还给数据源

常见的数据源（连接池）：DBCP、C3P0、BoneCP、Druid等

数据源开发的步骤

1. 导入数据源的坐标和数据库驱动坐标
2. 创建数据源对象
3. 设置数据源的基本连接数据
4. 使用数据源获取连接资源和归还连接资源

数据源创建演示（c3p0）

创建maven-web骨架项目

导入mysql、c3p0、druid、junit坐标

   <dependencies>
     <dependency>
       <groupId>mysqlgroupId>
       <artifactId>mysql-connector-javaartifactId>
       <version>5.1.32version>
     dependency>

     <dependency>
       <groupId>c3p0groupId>
       <artifactId>c3p0artifactId>
       <version>0.9.1.2version>
     dependency>

     <dependency>
       <groupId>com.alibabagroupId>
       <artifactId>druidartifactId>
       <version>1.1.10version>
     dependency>

     <dependency>
       <groupId>junitgroupId>
       <artifactId>junitartifactId>
       <version>4.11version>
       <scope>testscope>
     dependency>
   dependencies>

创建编写测试类

获取mybatis数据库的连接

package com.taotao.test;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.junit.Test;

import java.beans.PropertyVetoException;
import java.sql.Connection;

/**
 * create by 刘鸿涛
 * 2022/4/7 0:38
 */
public class DataSourceTest {
    @Test
    //测试手动创建 c3p0数据源
    public void test1() throws Exception {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        comboPooledDataSource.setDriverClass("com.mysql.jdbc.Driver");
        comboPooledDataSource.setJdbcUrl("jdbc:mysql://localhost:3306/mybatis?");
        comboPooledDataSource.setUser("root");
        comboPooledDataSource.setPassword("12345");
        Connection connection = comboPooledDataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }
}

测试运行

数据源创建演示（druid）

编写测试类

package com.taotao.test;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidPooledConnection;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.junit.Test;

import java.beans.PropertyVetoException;
import java.sql.Connection;

/**
 * create by 刘鸿涛
 * 2022/4/7 0:38
 */
public class DataSourceTest {
    @Test
    //测试手动创建 c3p0数据源
    public void test1() throws Exception {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        comboPooledDataSource.setDriverClass("com.mysql.jdbc.Driver");
        comboPooledDataSource.setJdbcUrl("jdbc:mysql://localhost:3306/mybatis?");
        comboPooledDataSource.setUser("root");
        comboPooledDataSource.setPassword("12345");
        Connection connection = comboPooledDataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }

    @Test
    //测试手动创建 druid数据源
    public void test2() throws Exception {
        DruidDataSource druidDataSource = new DruidDataSource();
        druidDataSource.setDriverClassName("com.mysql.jdbc.Driver");
        druidDataSource.setUrl("jdbc:mysql://localhost:3306/mybatis?");
        druidDataSource.setUsername("root");
        druidDataSource.setPassword("12345");
        DruidPooledConnection connection = druidDataSource.getConnection();
        System.out.println(connection);
        connection.close();
    }
}

测试运行

抽出耦合的数据源

新建文件

test - java - resources - jdbc.properties

编写测试类，加载properties配置文件

@Test
//测试手动创建 c3p0数据源(加载properties配置文件)
public void test3() throws Exception {
    //读取配置文件
    //ResourceBudle类是jdk util包自带的
    ResourceBundle rb = ResourceBundle.getBundle("jdbc");
    String driver = rb.getString("jdbc.driver");
    String url = rb.getString("jdbc.url");
    String username = rb.getString("jdbc.username");
    String password = rb.getString("jdbc.password");
    //创建数据源对象 设置连接参数
    ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
    comboPooledDataSource.setDriverClass(driver);
    comboPooledDataSource.setJdbcUrl(url);
    comboPooledDataSource.setUser(username);
    comboPooledDataSource.setPassword(password);
    Connection connection = comboPooledDataSource.getConnection();
    System.out.println(connection);
    connection.close();
}

测试运行

Spring配置数据源

可以将DataSource的创建权交由Spring容器去完成

导入Spring坐标

     <dependency>
       <groupId>org.springframeworkgroupId>
       <artifactId>spring-contextartifactId>
       <version>5.0.5.RELEASEversion>
     dependency>

创建编写Spring.xml

text-resources

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver">property>
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/mybatis?">property>
        <property name="user" value="root">property>
        <property name="password" value="12345">property>

    bean>
beans>

编写测试类

    @Test
    //测试Spring容器产生数据源对象
    public void test4() throws Exception{
        //获得Spring xml文件
        ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
        //使用id
        DataSource dataSource = (DataSource) app.getBean("dataSource");

        //反射获取，不太安全，比较方便
//        DataSource dataSource = app.getBean(DataSource.class);
        Connection connection = dataSource.getConnection();
        System.out.println(connection);
        connection.close();

    }

测试运行

抽取jdbc配置文件

applicationContext.xml加载jdbc.properties配置文件获取连接信息

首先，需要引入context命名空间和约束路径：

编写Spring.xml

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns:context="http://www.springframework.org/schema/context"

       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context  http://www.springframework.org/schema/context/spring-context.xsd">


    <context:property-placeholder location="classpath:jdbc.properties">context:property-placeholder>

    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${jdbc.driver}">property>
        <property name="jdbcUrl" value="${jdbc.url}">property>
        <property name="user" value="${jdbc.username}">property>
        <property name="password" value="${jdbc.password}">property>

    bean>
beans>

测试运行

总结

• 配置完后，提高耦合性，后期维护起来也相对简单，只需更改properties配置文件，即可对整个项目jdbc连接做出贡献